Colorimetric and Electrochemical Dual-Mode Detection of Thioredoxin 1 Based on the Efficient Peroxidase-Mimicking and Electrocatalytic Property of Prussian Blue Nanoparticles.

As a potent detection method for cancer biomarkers in physiological fluid, a colorimetric and electrochemical dual-mode sensing platform for breast cancer biomarker thioredoxin 1 (TRX1) was developed based on the excellent peroxidase-mimicking and electrocatalytic property of Prussian blue nanoparticles (PBNPs). PBNPs were hydrothermally synthesized using K3[Fe(CN)6] as a precursor and polyvinylpyrrolidone (PVP) as a capping agent. The synthesized spherical PBNPs showed a significant peroxidase-like activity, having approximately 20 and 60% lower Km values for 3,3',5,5'-tetramethylbenzidine (TMB) and H2O2, respectively, compared to those of horseradish peroxidase (HRP). The PBNPs also enhanced the electron transfer on the electrode surface. Based on the beneficial features, PBNPs were used to detect target TRX1 via sandwich-type immunoassay procedures. Using the strategies, TRX1 was selectively and sensitively detected, yielding limit of detection (LOD) values as low as 9.0 and 6.5 ng mL-1 via colorimetric and electrochemical approaches, respectively, with a linear range of 10-50 ng mL-1 in both strategies. The PBNP-based TRX1 immunoassays also exhibited a high degree of precision when applied to real human serum samples, demonstrating significant potentials to replace conventional HRP-based immunoassay systems into rapid, robust, reliable, and convenient dual-mode assay systems which can be widely utilized for the identification of important target molecules including cancer biomarkers.

Hyaluronic acid hydrolysis using vacuum ultraviolet TiO2 photocatalysis combined with an oxygen nanobubble system.

Advanced technologies for producing high-quality low molecular weight hyaluronic acid (LMW-HA) are required from the perspective of cost-efficiency and biosafety. Here, we report a new LMW-HA production system from high molecular weight HA (HMW-HA) using vacuum ultraviolet TiO2 photocatalysis with an oxygen nanobubble system (VUV-TP-NB). The VUV-TP-NB treatment for 3 h resulted in a satisfactory LMW-HA (approximately 50 kDa measured by GPC) yield with a low endotoxin level. Further, there were no inherent structural changes in the LMW-HA during the oxidative degradation process. Compared with conventional acid and enzyme hydrolysis methods, VUV-TP-NB showed similar degradation degree with viscosity though reduced process time by at least 8-fold. In terms of endotoxin and antioxidant effects, degradation using VUV-TP-NB demonstrated the lowest endotoxin level (0.21 EU/mL) and highest radical scavenging activity. This nanobubble-based photocatalysis system can thus be used to produce biosafe LMW-HA cost-effectively for food, medical, and cosmetics applications.

Optimization of phytic acid-crosslinked chitosan microspheres for oral insulin delivery using response surface methodology.

Although oral administration is favorable mode of insulin delivery, it is the most challenging route, owing to poor oral bioavailability. In this study, a chitosan (CS)-based insulin delivery system was developed by ionic crosslinking with phytic acid (PA). CS-PA microspheres were optimized with different crosslinking conditions of CS and PA using response surface methodology to retain insulin during preparation and gastric digestion. Furthermore, the in vitro release profile, morphological structure, cytotoxicity, and intestinal permeability of the optimized microspheres, and its hypoglycemic effect in diabetic rats were evaluated. Under optimal conditions, the entrapment efficiency was 97.1%, and 67.0% of insulin was retained in the microspheres after 2 h of gastric digestion followed by a sustained-release in intestinal fluid. Insulin was primarily distributed in the microsphere core with a monodisperse diameter of 663.3 µm. The microspheres increased the permeability of insulin across Caco-2/HT-29 monolayers by 1.6 times with negligible cytotoxicity. The microspheres had a relative pharmacological bioavailability of 10.6% and significantly reduced blood glucose levels with a long-lasting hypoglycemic effect after oral administration in diabetic rats. This study demonstrated that an optimized formulation of a simple ionic crosslinking system using CS and PA could facilitate efficient oral delivery of insulin.

Development of ginseng powder using high hydrostatic pressure treatment combined with UV-TiO2 photocatalysis.

BACKGROUND: Korean ginseng (Panax ginseng Meyer) powder is in rising demand because powder forms of foods are convenient to handle and are highly preservable. However, ginseng powder (GP) manufactured using the conventional process of air drying and dry milling suffers nutrient destruction and a lack of microbiological safety. The objective of this study was to prepare GP using a novel process comprised of UV-TiO2 photocatalysis (UVTP) as a prewashing step, wet grinding, high hydrostatic pressure (HHP), and freeze-drying treatments. METHODS: The effects of UVTP and HHP treatments on the microbial population, ginsenoside concentration, and physiological characteristics of GP were evaluated. RESULTS: When UVTP for 10 min and HHP at 600 MPa for 5 min were combined, initial 4.95 log CFU/g-fw counts of total aerobes in fresh ginseng were reduced to lower than the detection limit. The levels of 7 major ginsenosides in UVTP-HHP-treated GP were significantly higher than in untreated control samples. Stronger inhibitory effects against inflammatory mediator production and antioxidant activity were observed in UVTP-HHP-treated GP than in untreated samples. There were also no significant differences in CIELAB color values of UVTP-HHP-treated GP compared with untreated control samples. CONCLUSION: Combined processing of UVTP and HHP increased ginsenoside levels and enhanced the microbiological safety and physiological activity of GP.

Inactivation of Salmonella Typhimurium in fresh cherry tomatoes using combined treatment of UV-TiO2 photocatalysis and high hydrostatic pressure.

The antibacterial efficacy of UV-TiO2 photocatalysis pre-washing in a water-assisted system (UVT, 4.5 mW/cm2, 5-15 min) and high hydrostatic pressure (HHP, 300-500 MPa, 1 min at 25 °C) post-package combined treatment was evaluated against Salmonella Typhimurium inoculated onto whole cherry tomato surfaces and compared with chlorine disinfection (200 ppm). An air pump was fitted at the bottom of UVT reactor to create turbulent flow for rotation of fruits for uniform disinfection. UVT-HHP combined treatment at 500 MPa achieved bacterial reduction of more than 5 log via a synergistic effect, compared with chlorine disinfection. Lycopene and total phenolic contents and antioxidant activities were not significantly changed in tomatoes after any treatment. UVT-HHP combined treatment did not affect the surface color but caused softness in tomatoes. UVT pre-washing followed by HHP post-package treatment can be the effective intervention strategy alternative to conventional chlorine disinfection for production of ready-to-eat (RTE) fresh cherry tomatoes.

Efficacy of UV-TiO2 photocatalysis technology for inactivation of Escherichia coli K12 on the surface of blueberries and a model agar matrix and the influence of surface characteristics.

Surface disinfection of fresh blueberries is an important food safety challenge due to the delicate texture and short shelf life of these small fruits. A newly designed water-assisted photocatalytic reactor was developed for disinfection of fruits with a delicate texture and complex surface characteristics. Efficacy of UV-TiO2 photocatalysis was evaluated in comparison with UV alone for inactivation of Escherichia coli K12 (as a surrogate for Escherichia coli O157:H7) inoculated onto the surface of the blueberry skin, calyx, and an experimentally prepared agar matrix that was used as a model matrix. Influence of surface characteristics such as surface hydrophobicity and surface free energy on bacterial adhesion were also investigated. The initial bacterial population on all surfaces was approximately 7.0 log CFU/g. UV-TiO2 photocatalysis (4.5 mW/cm2) for 30 s achieved comparatively higher bacterial reductions of 5.3 log and 4.6 log CFU/g on blueberry skin and agar matrix surfaces, respectively, than 4.5 log and 3.4 log CFU/g reductions for UV alone (6.0 mW/cm2). Total phenolic and total anthocyanin contents of fruits were significantly increased after both UV-TiO2 and UV treatments, compared with water washed control fruits. UV-TiO2 photocatalysis technology is a non-chemical and residue-free method with reduced water usage for surface disinfection of fresh blueberries.

Nanoparticle-Patterned Multicompartmental Chitosan Capsules for Oral Delivery of Oligonucleotides.

Orally administered antisense therapy has been introduced as an effective approach for treating cancer in the gastrointestinal tract. However, its practical application has been limited by the instability of oligonucleotides and their inefficient delivery. To overcome these problems, we synthesized size-dependent, oligonucleotide nanoparticle-patterned chitosan/phytic acid (ODN/CS/PA) capsules with protective shields via a three-step process of self-assembly, nanoparticle encapsulation, and shell formation. The multicompartmental capsule size and oligonucleotide nanoparticle-loading pattern were controlled by applying different potentials during the electrostatic extrusion process used for nanoparticle encapsulation. Over 95% of encapsulated oligonucleotides were protected from nuclease digestion (DNase I) and, depending on their size, showed 40-75% protection against simulated gastric fluid. Their controlled release from capsules correlated with the cellular delivery of released nanoparticles and the inhibition of protein expression in cancer cells. Specifically, large capsules showed approximately 32-fold greater delivery to cancer cells than nonencapsulated nanoparticles. We also confirmed delivery of oligonucleotide nanoparticles to the small intestine and colon of rats following oral administration. These findings demonstrate that the multicompartmental ODN/CS/PA capsules can facilitate efficient oral delivery of oligonucleotides for cancer treatment.

Inactivation of Escherichia coli O157:H7 on Orange Fruit Surfaces and in Juice Using Photocatalysis and High Hydrostatic Pressure.

Nonpasteurized orange juice is manufactured by squeezing juice from fruit without peel removal. Fruit surfaces may carry pathogenic microorganisms that can contaminate squeezed juice. Titanium dioxide-UVC photocatalysis (TUVP), a nonthermal technique capable of microbial inactivation via generation of hydroxyl radicals, was used to decontaminate orange surfaces. Levels of spot-inoculated Escherichia coli O157:H7 (initial level of 7.0 log CFU/cm(2)) on oranges (12 cm(2)) were reduced by 4.3 log CFU/ml when treated with TUVP (17.2 mW/cm(2)). Reductions of 1.5, 3.9, and 3.6 log CFU/ml were achieved using tap water, chlorine (200 ppm), and UVC alone (23.7 mW/cm(2)), respectively. E. coli O157:H7 in juice from TUVP (17.2 mW/cm(2))-treated oranges was reduced by 1.7 log CFU/ml. After orange juice was treated with high hydrostatic pressure (HHP) at 400 MPa for 1 min without any prior fruit surface disinfection, the level of E. coli O157:H7 was reduced by 2.4 log CFU/ml. However, the E. coli O157:H7 level in juice was reduced by 4.7 log CFU/ml (to lower than the detection limit) when TUVP treatment of oranges was followed by HHP treatment of juice, indicating a synergistic inactivation effect. The inactivation kinetics of E. coli O157:H7 on orange surfaces followed a biphasic model. HHP treatment did not affect the pH, °Brix, or color of juice. However, the ascorbic acid concentration and pectinmethylesterase activity were reduced by 35.1 and 34.7%, respectively.

Enantioselective induction of SIRT1 gene by syringaresinol from Panax ginseng berry and Acanthopanax senticosus Harms stem.

Syringaresinol exists either exclusively as one enantiomer or enantiomeric mixtures in plant foods. We found that (+)-syringaresinol, but not (-)-syringaresinol, upregulates silent information regulator two ortholog 1 (SIRT1) gene expression, and thus, Panax ginseng berry with predominantly high contents of (+)-syringaresinol exhibits higher activity in inducing SIRT1 gene expression than Acanthopanax senticosus Harms stem with almost equal proportion of the two enantiomers. These findings highlight the importance of the absolute configuration of syringaresinol for the biological activity.